Rational design of a ratiometric fluorescent probe for imaging lysosomal nitroreductase activity.

Overexpressed nitroreductase (NTR) is often utilized to evaluate the hypoxic degree in tumor tissues, thus it is of great importance to develop high selective and efficient optical method to detect NTR. The dynamic fusion and function of lysosome promoted us to explore the possible appearance of NTR inside this organelle and to probe its behavior in a cellular context. In this work, a ratiometric fluorescent probe based on an extended π-π conjugation of a triphenylamine unit was designed for NTR detection and lysosomes imaging.